Conference Papers
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/6561
This collection contains abstracts of conference papers, presented at local and international conferences by the staff of the Faculty of Medicine
Browse
8 results
Search Results
Item Clinical and histopathological characteristics of cutaneous leishmaniasis in a group of military personnel in Sri Lanka(American Society of Tropical Medicine and Hygiene, 2015) Manamperi, N.H.; Fernando, C.S.; Pathirana, A.; Abeyewickreme, W.; de Silva, V.C.; Karunaweera, N.D.Cutaneous leishmaniasis (CL) is a newly established vector-borne parasitic disease in Sri Lanka. Military personnel have an occupational risk for CL due to being stationed in endemic areas and exposure to vectors outdoors. This study describes the clinical and histopathological features of CL in a group of military personnel. Thirty five patients with smear positive for Leishmania amastigotes were included, their data analyzed for clinical features and skin biopsies processed routinely for histology, examined at a conference microscope and classified into 4 groups using modified Ridley criteria for Leishmaniasis as: I-parasitized macrophages with variable lymphocytes and plasma cells; II-parasitized macrophages with lymphocytes, plasma cells and ill formed histiocytic granulomata; III-a mixture of macrophages (with or without parasites), lymphocytes, plasma cells and epithelioid granulomata; IV-epithelioid granulomatous response with a few lymphocytes and plasma cells but no amastigotes. Lesions were categorized by duration, as acute (< 6 months) or chronic (> 6 months). Study group composed of all males with a mean age of 32.6 years (range 22-47) and lesion duration of 5.6 months (range 1-24). Number of lesions varied from 1 to 6 with majority (71.4%, n= 25) having a single lesion. Nodular (37.1%, n=13) and nodulo-ulcerative (25.7%, n=9) lesions in upper limbs (68.6%, n=24) was the commonest presentation. Twenty nine (82.9%) of the biopsies were positive also by histology. Twenty two (62.9%) were acute and 13 (37.1%) chronic. Group I, II, III and IV patterns were seen in 14 (40%), 12 (34.3%), 5 (14.3%) and 4 (11.4%) respectively and 9 (40.9%), 9 (40.9%), 2 (9.1%) and 2 (9.1%) of acute lesions and 5 (38.5%), 3 (23.1%), 3 (23.1%) and 2 (15.4%) of chronic lesions respectively. Necrosis was not seen in any of the lesions. Majority in this group of military personnel with CL had single lesions affecting the upper limbs and sought treatment within 2 years of appearance of lesions. The histological picture varied from diffuse infiltration of parasitized macrophages admixed with chronic inflammatory cells to ill-formed histiocytic granulomata.Item Low prevalence of Hepatitis B and C molecular markers in a cohort of Sri Lankan patients with hepatocellular carcinoma(Sri Lanka Medical Association, 2007) Dassanayake, A.S.; Manamperi, A.; Gunawardena, N.K.; Abeyewickreme, W.; de Silva, A.P.; de Silva, H.J.INTRODUCTION: Hepatitis B (HBV) and C (HCV) infections are leading causes of hepatocellular carcinoma (HCC). Although HCV is the predominant aetiological factor in many parts of the world, HBV remains more important in South Asia. Detection of molecular markers is the most reliable means of diagnosing infection. Molecular studies on HBV and HCV infection in HCC have not been performed in Sri Lanka. OBJECTIVES: To investigate the prevalence of HBV and HCV using molecular markers of infection in a cohort of Sri Lankan patients with HCC. DESIGN, SETTING AND METHODS: 34 consecutive patients with HCC were investigated for evidence of HBV and HCV infection. In addition to serology, serum was tested for HBV DNA and HCV RNA by PCR (sensitivity 500 copies/ml serum) and RT-PCR (sensitivity 200 copies/ml serum ) respectively. A detailed clinical work-up, screening for diabetes mellitus and iron studies were also performed. RESULTS: Of the 34 patients, 32 (94%) -were males; median age was 68 years. All had evidence of background cirrhosis. Five had evidence of past or present HBV infection, four were HBV DNA positive, one was anti-HBc positive but HBV DNA negative, and one was HCV RNA positive. In addition, 23 (67%) had a history of alcohol abuse and 18 (52%) had long standing diabetes. None had evidence of haemochromatosis. CONCLUSIONS: Prevalence of HBV and HCV infection was low in this cohort of Sri Lankan patients with HCC. This is in keeping with the low prevalence of these infections in the community.Item Silent transmission as a risk factor affecting transmission of dengue fever.(Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, 2007) Hapangama, H.A.D.C.; Hapugoda, M.D.; Gunawardene, Y.I.N.S.; Premaratna, R.; Dayanath, M.Y.D.; Abeyewickreme, W.The global incidence of dengue fever has increased by more than four-folds over the last 30 years, making it the most threatening mosquito-borne viral disease at present. Objective of this study is to determine the role of silent transmission •on' incidence of dengue. A total of 40 households, living within a 300 m radius of seven selected ‘confirmed dengue cases at different dengue high risk localities in Gampaha District were recruited for this study. A minimum of three inhabitants were tested for anti-dengue antibodies using a commercial kit to determine the prevalence of silent transmission on dengue infection in each households. Entomological surveillance was carried out in all seven localities. Out of 40 households, 26 (65%) houses were positive for dengue viral infection. Total of 148 inhabitants (68 Males); mean age; 35.9 years were enrolled. Of the 148, 41 (27.7%) had evidence of exposure to dengue virus [positive for IgM: 28/41(68.4%), IgM'& IgG: 7/41(17%) and IgG: 6/41(14.6%)]. Out of 28 primary infections, 20(71.4%) were asymptomatic. Of the 7 secondary infections, 1(14.28%) was asymptomatic. Of the 6 previous exposures to dengue 4(66.67%) were asymptomatic. Of the 7 localities investigated, 1 had >50%, 4 had >25% and 2 had <25% clustering of cases. Ae. albopictus found in all seven localities and Ae. aegypti found only in two localities. This study suggests presence of silent transmission of dengue virus with a trend towards clustering around cases and also this shows that the presence of vectors increases the incidence of dengue.Item Impact of repeated annual Diethylcarbamazine-Albendazole mass treatment on transmission of Wuchereria bancrofti in the Gampaha district.(Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, 2007) Wijegunawardana, N.D.A.D.; Gunawardene, Y.I.N.S.; Abeyewickreme, W.Entomological and parasitological surveys are critical for the baseline evaluation of impact of repeated annual. Diethylcarbamazine-Albendazole mass treatment on the reduction of microfilaria density and level transmission of Wuchereria bancrofti in Culex quinquefaciatus. The objective of this study was to assess the current situation, following the mass drug administration programme in the Gampaha district, with regard to lymphatic filariasis, using entomological and parasitological data. A pilot survey was carried out using parasitological, 'clinical and entomological indicators in 21 sites in 7 Medical Officer of Health areas of Gampaha district to assess the current filariasis situation. The localities were selected from. the Medical Officer of Health areas based on previous data obtained from the regional Anti Filariasis Campaign office. Results indicate that 76.19% (16/21) sites were infested with mosquitoes positive for Wuchereria bancroft and the positivity of 1.44% (31/2157) was observed among the mosquitoes caught from households in the selected sites. The microfilariae wasa determined to be 15.5 per positive mosquito. The parasitological result was indicated 0.017 % prevalence of lymphatic fllariasis in the selected population. Data recorded by the Anti Filariasis Campaign Gampaha in 1994, suggested that significant decrease of infective rate, positivity of mosquito and microfilaria density, which are respectively 90%, 3.05% and 23. Study confirms that active transmission of Wuchereria bancrofti is currently taking place in the Gampaha district, despite, the mass drug administration Programme been implemented since 2002. This study highlights the urgent requirement of a proper screening programme combined with anti filarial treatment and vector control programme to minimize filarial morbidity and interrupt filarial transmission within the country.Item Patterns of monthly Culex mosquito density variation in Gampaha district, Sri Lanka.(Faculty of Tropical Medicine, Mahidol University, 2009) Wijegunawardana, N.D.A.D.; Gunawardene, Y.I.N.S.; Manamperi, A.; Abeyewickreme, W.BACKGROUND: The ecology, development, behavior, and survival of mosquitoes and the transmission dynamics of the diseases they transmit are strongly influenced by climatic factors. OBJECTIVE: The objective of this study was to identify the population density variation of Culex mosquitoes within a period of one year in Gampaha district, Sri Lanka together with potential climatic factors that influenced the Culex population density variation. METHODOLOGY: Culex mosquitoes were routinely collected on monthly basis from 9 sites in Gampaha district. Climate data was obtained from the Department of Meteorology. RESULTS: An exponential growth of Culex population densities was observed in all sites starting in December to February during the study period. The maximum density occurred in January and decreased from March until July. It again increased during August and thereafter decreased until December. Among the study sites the maximum Culex density (mosquitoes/man-hour) was observed in Hekiththa ranging between 89 to 22 and the minimum was from Kurukulawa ranging from 6 to 1. Climatic data suggest that temperature is a limiting factor for the Culex population growth while it was strongly influenced by the rain fall pattern. DISCUSSION: Similar Culex population density variation pattern was observed in all sites but exhibited enormous variation between sites, probably due to different local conditions. Also it was suggested that estimation of W, bancrofti transmission levels in Culex mosquitoes should be practiced in field settings where high mosquito density was observed. Since mosquito density appears difficult to be analyzed by individual dissection use of pool-screen PCR-ELISA would be a better method.Item GIS mapping of Lymphatic Filariasis endemic areas in Gampaha district, Sri Lanka; based on the epidemiological and entomological screening(Faculty of Tropical Medicine, Mahidol University, 2009) Wijegunawardana, N.D.A.D.; Gunawardene, Y.I.N.S.; Manamperi, A.; Abeyewickreme, W.BACKGROUND: The health issues related to vector borne diseases appear always to be related to space and time. Therefore it is ideal to link Geographical Information Systems (GIS) with epidemiological and entomological data to monitor spread of infection and target control strategies. OBJECTIVE: The objective of this study was to develop a site directed GIS map for lymphatic filariasis (Lf) dispersed areas in Gampaha district, Sri Lanka as a guide to target control activities. METHODOLOGY: Epidemiological and entomological screening of Lf was done in nine pre-identified endemic areas in Gampaha district, using night blood screening and pool-screening PCR-ELISA protocols respectively. RESULTS: Overall, 1073 (286 children, 787 adults) from 9 sites were examined. Mf-positive cases were detected in 2 sites, with a prevalence rate of 10.5% (Hekiththa) and 3.4% (Peliyagoda) with over 30% Mf prevalence in adult mosquito populations. The overall prevalence of mosquitoes with L1-L2 larvae of W. bancrofti ranged from 0%-8.54% by dissection and point estimates of infection prevalence, as assayed by PCR-ELISA, ranged from 0% - 35.4%. According to geographical data, the highest number of cases was found at altitudes between 2.5-3.5 m and highly populated areas where transmission appears to be taken place. Questionnaires indicated limited community awareness can be a reason for the fairly static infection rate prevalent in Peliyagoda sentinel site. DISCUSSION: The maps derived indicate the substantial extent as well as the marked variability in the geographical distribution of Lf in Gampaha, demonstrating site related trends.Item Application of nucleic acid technology (NAT) in the diagnosis of active viral replication in HBV and HCV infections and evidence for HBV surface antigen mutants(Sri Lanka Association for the Advancement of Science, 2008) Manamperi, A.; Gunawardene, Y.I.N.S.; Hapuarachchi, C.; Bandara, A.; Wellawaththage, C.; Abeyewickreme, W.; de Silva, J.Introduction: The community prevalence of Hepatitis B (HBV) and hepatitis C (HCV) infections, although considered low (< 1%) in Sri Lanka based on serological markers, pose a significant health threat to patients in high risk groups. The early diagnosis of active viral infection is crucial in such situations to prevent further transmission and to enable the clinicians to initiate successful therapeutic interventions. Objective: This study was carried out to investigate the usefulness of polymerase chain reaction (PCR) in the diagnosis of active viral replication in HBV and HCV infections. Methodology: All specimens from patients with serological evidence of hepatitis B (HBV surface antigen and/or antibodies for HBV core protein) or hepatitis C (antibodies for hepatitis C core protein-Anti-HCV) and referred to the Molecular Medicine Unit from May 2005 to May 2008 were analyzed by PCR and reverse-transcription PCR (RT-PCR) for HBV DNA (n=130) and HCV RNA (n=95) respectively. Results: Of the 130 patients tested, 57 (44%) were positive for HBV DNA. The positive group of patients included 10 renal transplant patients, 4 multiply transfused patients, 4 paediatric patients with lymphoma, and 1 patient with cirrhosis. Six HBV DNA positive patients had negative HBsAg serology profiles indicating the possibility of surface antigen mutant strains. The HBV DNA negative patients with positive serology profiles indicate sero-converted/ patients with resolved infections or false positive serology results. Of the 95 patients tested, 14 (15%) were positive for HCV RNA and included 3 paediatric patients with thalassaemia. HCV RNA negative, anti-HCV positive profiles reflect either false positive serology results (due to less specific antibody assays) or donors who have been exposed to HCV previously and subsequently resolved their infections. Conclusions: A major proportion of patients with serological markers for HBV have active viral infection whereas only relatively a minor proportion of patients with serological markers for HCV have active viral replication. We have also found the first possible evidence of hepatitis B surface antigen mutant strains. This underlines the importance of the nucleic acid based technology in the diagnosis and assessment of infection with or suspected to have hepatitis B or C infections. We also emphasize the importance of introducing NAT for screening donors for HBV DNA and HCV RNA to substantially lower the risk of acquiring HBV/HCV infection from a transfusion.Item Prevalence of Anopheline species in Ampara district, Sri Lanka(University of Kelaniya, 2012) Fernando, M.A.S.T.; Gunathilaka, P.A.D.H.N.; Hapugoda, M.D.; de Silva, B.G.D.N.K.; Wijeyerathne, P.; Abeyewickreme, W.Introduction: Investigating the presence of primary and secondary vectors of malaria in the selected areas where no entomological surveillance was carried out for about 30 years due to ethnic conflict. Objective: To study prevalence of malaria vector in Ampara District and to assess the risk of malaria in the area. Method: Surveillance was preformed from January 2011 to June 2012 in 4 selected areas (i.e. Panama, Thirukkovil, Mahaoya and Dehiattakandiya) in Ampara District. From each area 4 localities (total 16 localities) were selected for the sample collection in order to ensure full coverage of the District. Cattle Baited Hut Collection (CBHC) and Cattle Baited Net Collection (CBNC) were performed as sample collecting methods on monthly basis throughout the surveillance period. Results: Mosquito densities for each collected Anopheles species were calculated as density per hut or net for CBHT and CBNT respectively. 14 Anopheles species were recorded from CBHC with high prevalence for An. subpictus (68.58%), An. nigerrimus (14.02%) and An. vagus (6.73%). 16 Anopheles species were recorded from CBNC with high prevelance of An. nigerrimus (50.07%), An. peditaeniatus (16.12%), An. pseudojemesi (9.21%) and An. subpictus (7.68%). An. culicifacies (primary malaria vector in Sri Lanka) recorded with lesser densities but An. subpictus, the secondary vector for malaria in Sri Lanka was predominant thorough out this study. Conclusions: The presence of primary and secondary malaria vectors in the area may cause a malaria epidemic in these areas. Hence, it is essential to study the seasonal prevalence of Anopheles species in order to initiate timely controlling measures in Ampara District.